I didnt know that. I'm brand new to the frequency change option and so far havnt figured out how to manage the frequency. I want to be lower frequency, hopefully around the 12khz but dont know yet how to acomplish that. I am using the deep(number 6) program for thr lower frequencies but customized it some and enter on number 15 but I dont know if the frequencies stay the same after I customized it. The frequency shift on settings keep shifting. I set it to zero but when I lock it in it goes back to 3.